Two developments are focusing renewed attention and concern in Washington toward China's military buildup. Earlier this month, China's legislature passed a law authorizing military action to take control of Taiwan, if it moves toward independence or if all other efforts at reunification fail. And at the same time, the European Union wants to lift its arms embargo against China, which was imposed after the Tiananmen massacre in 1989.

A recent report prepared for the U.S. Defense Department says China is proceeding with a substantial military buildup, leading some experts to worry that 25 years after starting its economic reforms, China may soon have the means to project military power in new and, from the U.S. point of view, potentially dangerous ways.

According to the report issued by the Defense Department in November and made public in January, China has built a series of facilities and strategic relationships stretching to the south and west from its own coastal waters. The facilities and relationships involve Thailand, Cambodia, Burma, Bangladesh and Pakistan.

The report, prepared by a consulting firm for the office of Secretary of Defense Donald Rumsfeld, says the primary goals of China's strategy are to protect the sea lanes through which much of its oil travels and to build its capability for a possible confrontation with Taiwan. The report says China is working to make its navy capable of operating farther from Chinese shores, putting long-range cruise missiles on its new warships, building up its submarine fleet and developing modern undersea mine systems to help it take control of strategic areas of open water.

The Pentagon report also says China is building its air force with new long-range targeting systems and unmanned aircraft.

In addition, the New York Times reported this month that recent intelligence reports indicate China has conducted an ambitious ship-building program, including 23 new amphibious assault ships that could land troops and heavy equipment on Taiwan, and 13 new attack submarines that could limit the United States' ability to come to the island's aid in any conflict.

In recent testimony to a congressional committee, the new director of the CIA, Porter Goss, acknowledged that China's military buildup could "tilt the balance of power in the Taiwan Strait."

"Beijing's military modernization and military buildup, which I know have not gone unnoticed by this committee, are posing new questions for us," he said. "Improved Chinese capabilities seemingly threaten U.S. forces in the region. China's recent legislation on anti-secession speaks for itself."

The head of the Defense Department's intelligence agency, Vice Admiral Lowell Jacoby, agreed that China's continuing missile buildup would threaten not only Taiwan but also other military facilities in Asia, including those of the United States. The admiral also said China's ability to launch nuclear warheads against U.S. territory will increase 700 percent in the next 10 years.

"Many nations are modernizing and expanding their ballistic missile systems, and they are a key part of China's military modernization program," he said. "China continues to modernize its forces across a broad range of conventional and missile capabilities. And also those kinds of capabilities that allow them to coordinate the efforts of their military in a more sophisticated way than previously existed are a concern also."

China says its military buildup is not directed at any other nation. But it has toughened its rhetoric on Taiwan in recent months, and has passed a law threatening to use force to bring the island under its control.

All this leads some China experts, like Peter Brooks of the Heritage Foundation, to conclude that China's efforts to build its military have profound implications for the balance of power in the region.

"China seeks to develop a military that can deter, delay or deny American intervention in the Pacific, especially over the issue of Taiwan," he said.

Mr. Brooks told the Senate Foreign Relations Committee China is seeking all types of weaponry, and especially high-technology communications gear that can make its existing forces more effective.

"Chinese military modernization priorities center around power projection capabilities - submarines, surface combatants [ships], tactical air power and air defense, ballistic and cruise missiles, overhead satellites and space programs, information warfare, psychological operations, as well as doctrinal improvements for fostering joint operations, military operations, based on their observation of such things as Operation Iraqi Freedom," he added.

After repeated requests, the Defense Department and the U.S. Pacific Command declined to comment on the record on China's military buildup. But senior department officials, who requested anonymity, agreed that China has been involved in a substantial upgrade of its capabilities, particularly in the last five years. The officials say during that time China has more than doubled its official annual military budget to $30 billion. And the officials indicated China's real military spending is even higher.

China's two-and-a-half million member military has long been thought of as out of date in its equipment, strategies and tactics, and relatively ineffective as a result. But the U.S. defense officials who spoke this month say China is working hard to change that, and is closely watching the U.S. military campaigns in Iraq, Afghanistan and elsewhere to gain a better understanding of how modern militaries are organized and how modern wars are fought.

The officials say that is one reason the United States is so concerned about the European Union's plan to lift its arms embargo against China, a move U.S. officials say will speed China's military modernization and potentially endanger China's neighbors and U.S. forces in the Pacific.